The aim of the proposed work is to achieve a better understanding of the proliferative behavior and related properties of the neoplastic cells in different hematopoietic tumors. It is hoped that more complete information about cellular kinetics will permit not only formulation of more effective treatment schedules but will also lead to clearer definition of the fundamental abnormalities in the hematopoietic tumors and of the interrelationships between them. Patients with hematopoietic tumors will be studied before, during and following chemotherapy, using autoradiographic and continuous flow microfluorometric methods, to determine the kinetic changes caused by different drugs and with the goal of devising improved treatment schedules. Studies will also be conducted in vitro on established cell lines of human hematopoietic cells during their different growth phases and on fresh human normal lymphocytes and leukemic and lymphoma cells to determine the perturbations caused by different drugs and the influence of natural regulatory factors. Techniques are being developed to purify and isolate clonogenic cells from normal blood and bone marrow in order to characterize their properties and compare them with clonogenic cells derived from human hematopoietic tumors.